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Ion transport through electrolyte/polyelectrolyte multi-layers.

Femmer R, Mani A, Wessling M - Sci Rep (2015)

Bottom Line: Ion transport of multi-ionic solutions through layered electrolyte and polyelectrolyte structures are relevant in a large variety of technical systems such as micro and nanofluidic devices, sensors, batteries and large desalination process systems.EnPEn can robustly capture ion transport in sub-millimeter architectures with submicron polyelectrolyte layers.We proof the strength of EnPEn for three yet unsolved architectures: (a) selective Na over Ca transport in surface modified ion selective membranes, (b) ion transport and water splitting in bipolar membranes and (c) transport of weak electrolytes.

View Article: PubMed Central - PubMed

Affiliation: AVT Chemical Process Engineering, RWTH Aachen University, Turmstr. 46, 52064 Aachen, Germany.

ABSTRACT
Ion transport of multi-ionic solutions through layered electrolyte and polyelectrolyte structures are relevant in a large variety of technical systems such as micro and nanofluidic devices, sensors, batteries and large desalination process systems. We report a new direct numerical simulation model coined EnPEn: it allows to solve a set of first principle equations to predict for multiple ions their concentration and electrical potential profiles in electro-chemically complex architectures of n layered electrolytes E and n polyelectrolytes PE. EnPEn can robustly capture ion transport in sub-millimeter architectures with submicron polyelectrolyte layers. We proof the strength of EnPEn for three yet unsolved architectures: (a) selective Na over Ca transport in surface modified ion selective membranes, (b) ion transport and water splitting in bipolar membranes and (c) transport of weak electrolytes.

No MeSH data available.


Related in: MedlinePlus

Current-voltage behaviour of a BPM comprising a 2 nm junction for varying concentrations of salt.Membrane charge density is σAEM = σCEM = a) 0.1 M b) 1 M.
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f4: Current-voltage behaviour of a BPM comprising a 2 nm junction for varying concentrations of salt.Membrane charge density is σAEM = σCEM = a) 0.1 M b) 1 M.

Mentions: Figure 4 shows current voltage curves for varying salt concentration in the bulk liquid and various membrane charge densities. The onset of water splitting and related increase in current density is visible at 20 Vth. For a chosen potential, the overall potential drop can be attributed to the drop across the two boundary layers and the junction. The fraction of the overall drop occuring in each region is determined by the conductivity of the corresponding electrolyte solution. The conductivity in the junction layer can be assumed constant, since there will be almost no salt ions present and the autoprotolysis of water is close to equilibrium. The boundary layer conductivity increases with the bulk concentration of salt. Consequently, the potential drop across the junction layer increases as well. This results in an slightly earlier onset of water splitting, indicated by the offset of the current voltage curves in both diagrams.


Ion transport through electrolyte/polyelectrolyte multi-layers.

Femmer R, Mani A, Wessling M - Sci Rep (2015)

Current-voltage behaviour of a BPM comprising a 2 nm junction for varying concentrations of salt.Membrane charge density is σAEM = σCEM = a) 0.1 M b) 1 M.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481379&req=5

f4: Current-voltage behaviour of a BPM comprising a 2 nm junction for varying concentrations of salt.Membrane charge density is σAEM = σCEM = a) 0.1 M b) 1 M.
Mentions: Figure 4 shows current voltage curves for varying salt concentration in the bulk liquid and various membrane charge densities. The onset of water splitting and related increase in current density is visible at 20 Vth. For a chosen potential, the overall potential drop can be attributed to the drop across the two boundary layers and the junction. The fraction of the overall drop occuring in each region is determined by the conductivity of the corresponding electrolyte solution. The conductivity in the junction layer can be assumed constant, since there will be almost no salt ions present and the autoprotolysis of water is close to equilibrium. The boundary layer conductivity increases with the bulk concentration of salt. Consequently, the potential drop across the junction layer increases as well. This results in an slightly earlier onset of water splitting, indicated by the offset of the current voltage curves in both diagrams.

Bottom Line: Ion transport of multi-ionic solutions through layered electrolyte and polyelectrolyte structures are relevant in a large variety of technical systems such as micro and nanofluidic devices, sensors, batteries and large desalination process systems.EnPEn can robustly capture ion transport in sub-millimeter architectures with submicron polyelectrolyte layers.We proof the strength of EnPEn for three yet unsolved architectures: (a) selective Na over Ca transport in surface modified ion selective membranes, (b) ion transport and water splitting in bipolar membranes and (c) transport of weak electrolytes.

View Article: PubMed Central - PubMed

Affiliation: AVT Chemical Process Engineering, RWTH Aachen University, Turmstr. 46, 52064 Aachen, Germany.

ABSTRACT
Ion transport of multi-ionic solutions through layered electrolyte and polyelectrolyte structures are relevant in a large variety of technical systems such as micro and nanofluidic devices, sensors, batteries and large desalination process systems. We report a new direct numerical simulation model coined EnPEn: it allows to solve a set of first principle equations to predict for multiple ions their concentration and electrical potential profiles in electro-chemically complex architectures of n layered electrolytes E and n polyelectrolytes PE. EnPEn can robustly capture ion transport in sub-millimeter architectures with submicron polyelectrolyte layers. We proof the strength of EnPEn for three yet unsolved architectures: (a) selective Na over Ca transport in surface modified ion selective membranes, (b) ion transport and water splitting in bipolar membranes and (c) transport of weak electrolytes.

No MeSH data available.


Related in: MedlinePlus